scholarly journals Development and evaluation of flux enhancement and cleaning strategies of woven fibre microfiltration membranes for raw water treatment in drinking water production

2015 ◽  
Author(s):  
◽  
Kumnandi Pikwa
Keyword(s):  
Membrane Filtration ◽  
Pure Water ◽  
Aeration Rate ◽  
Raw Water ◽  
Flux Enhancement ◽  
Average Flux ◽  
Particle Adsorption ◽  
Filtration Unit ◽  
Feed Samples ◽  
Pore Plugging

Woven Fibre Microfiltration (WFMF) membranes have several advantages over its competitors with respect to durability, making it a favourable alternative for the developing world and operation during rough conditions. Wide application of membrane technology has been limited by membrane fouling. The durability of the WFMF membrane allows more options for flux enhancement and cleaning methods that can be used with the membranes even if they are vigorous. Therefore, the purpose of this work was to develop and evaluate flux enhancement and cleaning strategies for WFMF membranes. Feed samples with high contents of organics and turbidity were required for the study. Based on this, two rivers which are Umkomaasi and Duzi River were identified to satisfy these criteria. A synthetic feed with similar fouling characteristics as the two river water was prepared and used for this study. The synthetic feed solution was made up of 2 g/ℓ of river clay in tap water and 0.5% domestic sewerage was added into the solution accounting for 2% of the total volume. A membrane filtration unit was used for this study. The unit consisted of a pack of five membrane modules which were fully immersed into a 100 litres filtration tank. The system was operated under gravity and the level in the filtration tank was kept constant by a level float. The study focused on evaluating the performance of the woven fibre membrane filtration unit with respect to its fouling propensity to different feed samples. It also evaluated and developed flux enhancement and cleaning strategies and flux restoration after fouling. The results were compared to a base case for flux enhancement and pure water fluxes for cleaning. The WFMF membrane was found to be prone to both internal and external fouling when used in the treatment of raw water (synthetic feed). Internal fouling was found to occur quickly in the first few minutes of filtration and it was the major contributor for the loss of flux from the WFMF membrane. The fouling mechanism responsible for internal fouling was found to be largely pore blocking and pore narrowing due to particle adsorption on/in the membrane pores. The structure (pore size, material and surface layout) of the WFMF membrane was found to be the main cause that made it prone to internal fouling. The IV major fouling of the WFMF membrane was due to internal fouling, a high aeration rate of 30 ℓ/min had minimal effect on the fouling reduction. An aeration rate of 30 ℓ/min improved the average flux by only 36%, where a combination of intermittent backwashing with brushing and intermittent backwashing with aeration (aeration during backwashing only) improved average flux by 187% and 135% respectively. Pre-coating the WFMF membrane with lime reduced the effects of pore plugging and particle adsorption on the membrane and improved the average flux by 66%. The cleaning strategies that were most successful in pure water flux (PWF) recovery were high pressure cleaning and a combination of soaking and brushing the membrane in a 0.1% NaOCl (desired) solution. PWF recovery by these two methods was 97% and 95% respectively. Based on these findings, it was concluded that the WFMF membrane is susceptible to pore plugging by colloidal material and adsorption/attachment by microbiological contaminants which took effect in the first hour of filtration. This led to a 50% loss in flux. Also, a single flux enhancement strategy proved insufficient to maintain a high flux successfully. Therefore, combined flux enhancement strategies yielded the best results.

Leading the City of Baltimore into the 21st Century: Flexible Treatment Solutions and Integrated Raw Water Management

2010 ◽  
Vol 5 (4) ◽  
Author(s):  
J. L. Manuszak ◽  
M. MacPhee ◽  
S. Liskovich ◽  
L. Feldsher
Keyword(s):  
Water Management ◽  
Water Quality ◽  
Water Supply ◽  
Conceptual Design ◽  
Membrane Filtration ◽  
Treatment Plant ◽  
Low Pressure ◽  
Management Tool ◽  
Raw Water ◽  
The City

The City of Baltimore, Maryland is one of many US cities faced with challenges related to increasing potable water demands, diminishing fresh water supplies, and aging infrastructure. To address these challenges, the City recently undertook a $7M study to evaluate water supply and treatment alternatives and develop the conceptual design for a new 120 million gallon per day (MGD) water treatment plant. As part of this study, an innovative raw water management tool was constructed to help model source water availability and predicted water quality based on integration of a new and more challenging surface water supply. A rigorous decision-making approach was then used to screen and select appropriate treatment processes. Short-listed treatment strategies were demonstrated through a year-long pilot study, and process design criteria were collected in order to assess capital and operational costs for the full-scale plant. Ultimately the City chose a treatment scheme that includes low-pressure membrane filtration and post-filter GAC adsorption, allowing for consistent finished water quality irrespective of which raw water supply is being used. The conceptual design includes several progressive concepts, which will: 1) alleviate treatment limitations at the City's existing plants by providing additional pre-clarification facilities at the new plant; and 2) take advantage of site conditions to design and operate the submerged membrane system by gravity-induced siphon, saving the City significant capital and operations and maintenance (O&M) costs. Once completed, the new Fullerton Water Filtration Plant (WFP) will be the largest low-pressure membrane plant in North America, and the largest gravity-siphon design in the world.

Ammonia Removal from Raw Water by using Adsorptive Membrane Filtration Process

2021 ◽  
pp. 118757
Author(s):  
Rosiah Rohani ◽  
Izzati Izni Yusoff ◽  
Nadiah Khairul Zaman ◽  
Arshid Mahmood Ali ◽  
Nadiatul Atalia Balqis Rusli ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Ammonia Removal ◽  
Raw Water ◽  
Filtration Process ◽  
Adsorptive Membrane

Membrane filtration of wastewater effluents for reuse: effluent organic matter rejection and fouling

2001 ◽  
Vol 43 (10) ◽  
pp. 225-232 ◽  
Author(s):  
C. Jarusutthirak ◽  
G. Amy
Keyword(s):  
Organic Matter ◽  
Membrane Filtration ◽  
Treated Wastewater ◽  
High Concentration ◽  
Effluent Organic Matter ◽  
Dead End ◽  
Flux Decline ◽  
Uf Membranes ◽  
Stirred Cell ◽  
Filtration Unit

The reuse of treated wastewater to augment natural drinking water supplies is receiving serious consideration. Treatment of secondary and tertiary effluent by membrane filtration was investigated by assessing nanofiltration (NF) membrane and ultrafiltration (UF) membranes in bench-scale experiments. It was found that secondary and tertiary effluent contained high concentration of effluent organic matter (EfOM), contributing EfOM-related fouling. Flux decline and EfOM rejection tests were evaluated, using a dead-end stirred cell filtration unit. Surface charge and molecular weight cut-off (MWCO) of membranes were significant factors in membrane performance including permeability and EfOM-rejection.

scholarly journals Distillate Flux Enhancement of Direct Contact Membrane Distillation Modules with Inserting Cross-Diagonal Carbon-Fiber Spacers

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 973
Author(s):  
Chii-Dong Ho ◽  
Luke Chen ◽  
Jun-Wei Lim ◽  
Po-Hung Lin ◽  
Pin-Tsen Lu
Keyword(s):  
Carbon Fiber ◽  
Direct Contact ◽  
Pure Water ◽  
Water Productivity ◽  
Membrane Distillation ◽  
Design Parameters ◽  
Countercurrent Flow ◽  
Flux Enhancement ◽  
Direct Contact Membrane Distillation ◽  
Theoretical Predictions

A new design of direct-contact membrane distillation (DCMD) modules with cross-diagonal carbon-fiber spacers of various hydrodynamic angles in flow channels to promote turbulence intensity was proposed to enhance pure water productivity. Attempts to reduce the temperature polarization coefficient were achieved by inserting cross-diagonal carbon-fiber spacers in channels, which create wakes and eddies in both heat and mass transfer behaviors to enhance the permeate flux enhancement. A simplified equation was formulated to obtain the theoretical predictions of heat transfer coefficients in the current DCMD device. The permeate fluxes and temperature distributions of both hot and cold feed streams are represented graphically with the inlet volumetric flow rate and inlet temperature of the hot saline feed stream as parameters. The higher distillate flux of countercurrent-flow operations for saline water desalination was accomplished as compared to the concurrent-flow operations of various hydrodynamic angles. The results show that the agreement between the theoretical predictions and experimental results is reasonably good. The effects of countercurrent-flow operations and inserting carbon fiber spacers have confirmed technical feasibility and device performance enhancement of up to 45%. The influences of operating and design parameters on the pure water productivity with the expense of energy consumption are also discussed.

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

scholarly journals Membrane Filtration Enhanced Hydrometallurgical Recovery Process of Indium from Waste LCD Panels

2020 ◽  
Vol 6 (4) ◽  
pp. 576-588
Author(s):  
Jussi Lahti ◽  
Sergio Vazquez ◽  
Sami Virolainen ◽  
Mika Mänttäri ◽  
Mari Kallioinen
Keyword(s):  
Membrane Filtration ◽  
Liquid Crystal Display ◽  
Recovery Process ◽  
Indium Content ◽  
Liquid Extraction ◽  
Fast Kinetics ◽  
Liquid Liquid Extraction ◽  
Extraction Step ◽  
Dissolved Organic Compounds ◽  
Filtration Unit

Abstract Insufficient recycling of a continuously increasing amount of liquid crystal display (LCD) waste leads to the waste of potentially recyclable materials, especially rare and critical indium. Moreover, landfilling of LCD waste increases the potential for environmental risk. This paper describes a recycling process combining membrane filtration unit processes to hydrometallurgical indium recovery process. The LCD panels were crushed and leached with 1 M H2SO4. 97.4% yields on average were obtained, and a novel finding was made about fast kinetics (2 min for the maximum indium yield). Ultrafiltration was used to remove the dissolved organic material from the leachate, which was concentrated with nanofiltration before liquid–liquid extraction for indium purification. The results showed that commercial polymeric membranes removed more than 90% (from over 3000 mg/L to under 200 mg/L) of the dissolved organic compounds, thus potentially significantly diminishing the detriments caused by these compounds in the liquid–liquid extraction step. The concentration of the leachate with nanofiltration enables the use of smaller processing equipment and to save chemicals in the further steps of the process. The indium content in the leachate was more than five times higher after nanofiltration than after leaching (126 mg/L vs. 677 mg/L). In liquid–liquid extraction, the phase separation took place in only 34 s with the membrane-treated leachate, while with the untreated leachate it remained incomplete even after three hours. The purity of indium was increased from 10 to 74%. From the obtained HCl solution, a 95.5% pure indium product with 69.3% yield was obtained by cementation. Graphical Abstract

Pretreatment processes for membrane filtration of raw water containing manganese

2001 ◽  
Vol 1 (5-6) ◽  
pp. 341-348 ◽  
Author(s):  
S. Takizawa ◽  
L. Fu ◽  
N. Pradhan ◽  
T. Ike ◽  
M. Ohtaki ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Manganese Concentration ◽  
Fluidised Bed ◽  
Raw Water ◽  
Biological Pretreatment ◽  
Manganese Removal ◽  
Time Required

Experimental studies on chemical and biological pretreatments in membrane filtration processes were carried out to removal manganese contained in raw water and to prevent membrane fouling due to manganese. Two types of the pretreatment reactors, i.e. the fluidised-bed and fixed-bed configurations, were compared in the biological pretreatment experiments. New synthetic media (tubular polypropylene, I.D. 3 mm, O.D. 4 mm, length 5 mm) were used in all three experiments as a manganese-oxidising catalyst. The chemical pretreatment using sodium hypochlorite was effective in manganese removal and controlling membrane fouling; more than 0.8 mg-Cl2/L of chlorine dose was necessary to bring the manganese concentration from 0.4 mg/L in raw water to less than 0.05 mg/L. The biological pretreatment for manganese removal required a long start-up period of more than 40 days. The fixed-bed biological pretreatment was superior in manganese removal and in control of membrane fouling to the fluidised-bed biological pretreatment, which showed wash-out of the attached bacteria resulting in membrane fouling. The linear velocity and the empty-bed retention time required for the treatment of 0.14 mg-Mn/L in the fixed-bed biological pretreatment was 206 m/d and 8.0 minutes, respectively.

On the Adsorption Capability of Powder Activated Carbon for Phenol

2014 ◽  
Vol 709 ◽  
pp. 422-425
Author(s):  
Shao Fen Zhong ◽  
Jian Wen Mo ◽  
Yang Ping Li
Keyword(s):  
Activated Carbon ◽  
High Performance ◽  
Solid Phase ◽  
Pure Water ◽  
Equilibrium Concentration ◽  
Impact Factors ◽  
Raw Water ◽  
Adsorption Model ◽  
Powder Activated Carbon ◽  
Adsorption Capability

Using solid phase extraction and high performance liquid chromatography (HPLC), this paper studies the adsorption capability of activated carbon to phenol. The phenol wastewater is simulated with raw water and pure water, respectively. In detail, we examine impact factors including adsorption time, activated carbon dosage, equilibrium concentration of phenol. Using the adsorption principles from the aspect of kinetics, our study shows that adsorption of powder activated carbon to phenol conforms to the Fran Delhi Freundrich adsorption model.

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